"What you see happening is congressional committees are now beginning to take the place of prosecutors, and that's dangerous for us all," Graham told host Sean Hannity.

Graham, the Senate Judiciary chairman, was criticized earlier this week when he said: "[I]f I were Donald Trump Jr.'s lawyer I would tell him, 'You don't need to go back into this environment anymore, you've been there for hours and hours and hours. And nothing being alleged here changes the outcome of the Mueller investigation."

Graham noted that Senate Intelligence Committee Chairman Richard Burr, R-N.C. - who issued the subpoena and was hit with swift backlash among his own party's ranks - is a "good friend," a "wonderful fellow" and an accomplished head of the panel.

"[Burr] is going to issue a good report," Graham said of the committee's own investigation into links between the Trump campaign and Russian officials.

"They want to impeach Barr. They want him to resign," Graham said of a number of the Democrats. "They want me to resign. And, they think [Supreme Court Justice] Brett Kavanaugh was Bill Cosby in high school ... These people are going nuts."